1. Field of the Disclosure
The following disclosure relates generally to medical devices, systems and methods, including medical instruments for use in performing spinal bone fusion. More specifically, the disclosure relates to a decorticating instrument and a method and system for guiding the instrument to a desired location.
2. Background
Surgical intervention is sometimes required in order to repair or provide additional structural support along the spinal column in cases where a portion of the patient's intervertebral anatomy has become weakened, diseased, or destroyed. Such support systems are also commonly used following a discectomy, where an intervertebral disc is surgically removed.
Posterior lumbar interbody fusion is open-back surgery used to alleviate the symptoms associated with impinged or irritated nerve tissue in the lower (lumbar) back. From an entry point in the back (posterior), the affected vertebrae are permanently connected, or fused, using a bone graft in order to mitigate the instability caused by a spinal condition such as degenerative disc disease.
Patients who undergo this type of lumbar fusion can expect the following:
a. A three- to six-inch incision is made along the lower back, usually parallel with the lumbar spine.
b. The laminae, the spinous process, and a portion of the facet joints are removed from the vertebra to allow access to the intervertebral disc.
c. The damaged or diseased portion of the disc is removed (called a discectomy), but a section of the fibrous disc wall is left intact to aid in bone graft containment.
d. Bone grafts are inserted into the area vacated by the disc; morselized or granular bone might be added to fill the area.
e. Metal screws are attached to the pedicles of the adjacent vertebrae, and rods are inserted through the screws to hold the vertebrae in place.
f. The bone graft grows over time, forming a bridge or fusion between the vertebrae.
In other minimally invasive approaches, percutaneous screws are employed but the procedure does not involve fusion, merely stabilization.
In addition to fixation or stabilization of the joint, it is beneficial to try to stimulate bone growth between the adjacent vertebrae. To do so, spine surgeons use bone graft material in addition to fixation devices. Bone graft doesn't heal or fuse the spine immediately; instead, bone graft provides a foundation or scaffold for the patient's body to grow new bone. Bone graft can stimulate new bone production. When new bone grows and solidifies, fusion occurs. Although instrumentation (e.g., screws, rods) is often used for initial stabilization (post-operative), it is the healing of bone that welds vertebrae together to create long-term stability. There are two general types of bone grafts: real bone and bone graft substitutes. Real bone can come from the patient (autograft) or from a donor bone (allograft). Also used in these types of surgery are bone substitute, osteoinductive agent, and bone cement.
There is a need for improved systems and methods for lumbar interbody fusion.